Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual Servedby tem uma autoridade local de Thurrock e uma estação de Ockendon?
 ###Tabelas: CREATE TABLE "sandy_bridge_dual-core"_32_nm ("sandy_bridge_dual-core"_32_nm_id AUTO_INCREMENT PRIMARY KEY, Model number VARCHAR, sSpec number VARCHAR, Cores VARCHAR, Frequency VARCHAR, Turbo VARCHAR, L2 cache VARCHAR, L3 cache VARCHAR, GPU model VARCHAR, GPU frequency VARCHAR, Socket VARCHAR, I/O bus VARCHAR, Release date VARCHAR, Part number(s) VARCHAR, Release price ( USD ) VARCHAR) CREATE TABLE stations (stations_id AUTO_INCREMENT PRIMARY KEY, Station VARCHAR, Local authority [a ] VARCHAR, Servedby VARCHAR, Station users 2004–05 INT, Station users 2005–06 INT) CREATE TABLE competition_timeline (competition_timeline_id AUTO_INCREMENT PRIMARY KEY, Competition VARCHAR, 1970–71 VARCHAR, 1971–72 VARCHAR, 1972–73 VARCHAR, 1973–74 VARCHAR, 1974–75 VARCHAR, 1975–76 VARCHAR, 1976–77 VARCHAR, 1977–78 VARCHAR, 1978–79 VARCHAR, 1979–80 VARCHAR, 1980–81 VARCHAR, 1981–82 VARCHAR, 1982–83 VARCHAR, 1983–84 VARCHAR, 1984–85 VARCHAR, 1985–86 VARCHAR, 1986–87 VARCHAR, 1987–88 VARCHAR, 1988–89 VARCHAR, 1989–90 VARCHAR, 1990–91 VARCHAR, 1991–92 VARCHAR, 1992–93 VARCHAR, 1993–94 VARCHAR, 1994–95 VARCHAR, 1995–96 VARCHAR, 1996–97 VARCHAR, 1997–98 VARCHAR, 1998–99 VARCHAR, 1999–00 VARCHAR, 2000–01 VARCHAR, 2001–02 VARCHAR, 2002–03 VARCHAR, 2003–04 VARCHAR, 2004–05 VARCHAR, 2005–06 VARCHAR, 2006–07 VARCHAR, 2007–08 VARCHAR, 2008–09 VARCHAR, 2009–10 VARCHAR, 2010–11 VARCHAR, 2011–12 VARCHAR) CREATE TABLE bolt_thrust_estimations_for_various_pistol_revolver_cartridges (bolt_thrust_estimations_for_various_pistol_revolver_cartridges_id AUTO_INCREMENT PRIMARY KEY, Chambering VARCHAR, P1 diameter (mm) VARCHAR, A external (cm 2 ) VARCHAR, P max ( bar ) INT, F bolt ( kgf ) INT, F bolt VARCHAR) CREATE TABLE eighth_round (eighth_round_id AUTO_INCREMENT PRIMARY KEY, Pick INT, Team VARCHAR, Player VARCHAR, Position VARCHAR, College VARCHAR)  
SELECT Servedby FROM stations WHERE Local authority [a ] = thurrock AND Station = ockendon